This case involves a smoker who purchased an e-cigarette that exploded in their mouth. The smoker went to a shop that sold e-cigarette materials and purchased a mod that the shop assembled for them with a specific type of battery. Following the explosion, it was discovered that another battery had been put into the e-cigarette, different from the type originally issued to the smoker by the shop. An expert in e-cigarette models and batteries was asked to review the battery and determine if the e-cigarette had been modified, as well as provide insight into the origin of the battery.
Question(s) For Expert Witness
- 1. How would you determine if an e-cigarette has been modified, as well as the origin of the battery?
Expert Witness Response E-189275
To further evaluate the situation, several clarifications would be needed.
a) What mod was reportedly installed by the shop?
b) Is it possible to attain a shop-issued battery for comparison and testing?
c) What is the condition of the damaged second battery?
Moving forward, a physical comparison of the batteries sold at the shop and the remnant battery would be needed. 18650 type cylindrical lithium cells often vary in cell wrapping, laser etches, and stamping. Past the aesthetics, 18650 type cells have a wide range of construction methods and cathode/vent (top of the cell). The physical dimensions (length, diameter) can be used to identify a specific cell. The top of a cell can feature several different variations of CIDs (current interruption device), or be unprotected. Using these methods is generally sufficient in identifying different cells. If further investigation is required, the cell could be taken apart and internal components measured.
To determine if the device had been modified, we would need to define what it means to modify an e-cigarette in this case. If changing the battery cell is a significant alteration to the shop’s mod, would something noticeable have been broken such as a sticker or label? If we are looking for a mechanical mod, we can compare the mechanical structure to a new e-cigarette and trace the circuitry to see if anything has been added or removed in the path of current. A thorough examination of the shop’s mod is required for this determination.
Expert Witness Response E-189794
E-cigarette design elements, such as the voltage regulator, the electronics, the battery, and the heating element, can differ depending on the type or model. When the cigarette is opened or modified, the voltage regulator or electronics could be damaged such that their output applies a voltage and current beyond the capability of the heating element. The regulator and electronics need to be inspected to see if there are any changes to the parts such scars on the board, missing parts, re-soldering and to see if they are outputting the correct voltage. There are many distinguishing features to battery cells that can vary between suppliers and cell designs including: the coating weight of the active material on the electrode foils, the foil thickness, the composition of the active materials, the type and thickness of the separator, the type of welding of the electrodes to the current collectors, etc. These items can be compared to both batteries and other e-cigarette batteries on the market to determine if the battery was from the original supplier or a different supplier manufacturing the same format.